Question

a fair coin is tossed thrice find the probability of getting 2 heads or at least one head

Answer 1

n(s) = (HHH,HHT,HTH,THH,TTT,HTT,THT,TTH)
= (8)
Let A be probability for getting 2 head
n(A)=3
P(A)=n(A)/n(s)=3/8

Let B be probality for getting atleast one head
n(B)=7
P(B)= 7/8

Answer 2

(n (s)=(HHH, HHT ,TTT, HTH ,THT, TTH, TTH, HTT)=8
Let event A be the probability of getting
2 heads
P (A)=3/8
similarly Let event B BEHAVING PROBABLITY OF ATLEAST ONE HEAD
Event B=(HHH,HHT,HTH,THT,TTH, HTT)
n (B)=7
p (B)=7/8